Well, she's not a Batman villain, actually, she's a Steel villain. I don't know if you've ever read the whole 'Death of Superman' storyline, but she first showed up during the 'Reign of the Supermen' bit - she was John Henry Irons's ex-lover and ex-colleague at the arms company where he used to work. She stole some of his old designs, and started manufacturing them and selling them on the streets of Metropolis as 'Toastmasters', prompting horrific gang violence, which prompted John Henry to build the Steel armor. I know she showed up afterwards in the Steel series, but as I don't know much about that, I'm not sure how much impact she had. She's a classic femme fatale - slinky dress, talent for wrapping men round her little finger, ever-present cigarette holder, the works. (She's also interesting in that she's one of only two only albino African Americans in comics that I can think of, the other being Tombstone from Spider-Man.)